bvillercr, How do keep the transmission on your procharger together? Have you guys had any problems when you have to pedal the car or go to shift? I picked up a F2 unit, and I am thinking about going away from the gilmer belts that they only run with to a serpentine belt so I can get some slip. I have herd stories of the transmission blowing on high RPM shifts.

On our new Procharger F3R-139, we haven't put any runs on it. On our old D2's the only problem we had was running two inch belts, but we also ran two blowers on that one belt. Once we went to the 3 inchers we haven't had any problems. We also try to back off the throttle just a bit before we shift. The only real problem we had was breaking the input shaft on our tranny from the power of the Procharger. The serpentine belt will work as long as it doesn't slip, they use the Gilmer for a good reason.

bvillercr, How do keep the transmission on your procharger together? Have you guys had any problems when you have to pedal the car or go to shift? I picked up a F2 unit, and I am thinking about going away from the gilmer belts that they only run with to a serpentine belt so I can get some slip. I have herd stories of the transmission blowing on high RPM shifts.

maguromic We have had plenty of problems over the years with the centrifugals mostly from driving two blowers with one belt. The problem is that the driver side blower drives the passenger side blower putting twice the power requirements on it. So the driver side is the one we usually have problems with. When we went 288 the overdrive trans slipped causing the engine to over rev catching a valve -backfiring and blowing the blowers off. none of the problems we've had could be blamed on the manufactures because we were using two blowers to get the cfm and boost needed for our big engine,which they were not designed for.We were real happy when procharger made the F3R-139 4000 cfm blower which enables us to use just one blower. Good luck with your F2 what motor and car? The WW2 aero engines had slip clutches to take the shock loads off the trans gears when they shifted into high blower gear. I wonder if we'll ever catch up?

Thanks for the info. My concern was that a friend of mine was racing up Piles Peak last year and he had a F1R and at high RPM shifts he blew the transmission in the head unit. For this year he built a belt drive gear system for the transmission. Also Doug Robinson mentioned that he had problems with his hybrid supercharger till he went to a "V" belt.

My F2 is going on a GMC XO motor and still haven't decided to build a gear drive and eliminate the belt on the supercharger or some style of belt. Still investigating the problems, it seems that the shaft in the transmission that the gears ride on is the culprit. Its too small for the high rpm and when you go to shift the shaft flexes throwing the gear alignment off and BOOM. I was reading that the early Miller and Offy blowers had very smiler problems till they devised way to fix it.

Thanks for the info. My concern was that a friend of mine was racing up Piles Peak last year and he had a F1R and at high RPM shifts he blew the transmission in the head unit. For this year he built a belt drive gear system for the transmission. Also Doug Robinson mentioned that he had problems with his hybrid supercharger till he went to a "V" belt.

My F2 is going on a GMC XO motor and still haven't decided to build a gear drive and eliminate the belt on the supercharger or some style of belt. Still investigating the problems, it seems that the shaft in the transmission that the gears ride on is the culprit. Its too small for the high rpm and when you go to shift the shaft flexes throwing the gear alignment off and BOOM. I was reading that the early Miller and Offy blowers had very smiler problems till they devised way to fix it.

I'm not to familiar with the F2 but i believe the gear case is machined from solid billitt as our F3R 139 is, go to page 6 of this build to see comparison between the F3R and one of our D2's. The gear case is way bigger than the D2 and we didn't have problems with the D2's which were machined castings.

How many times are you going to shift on a bville run compared to Pikes peak? There is a company in Arizona that makes a gear drive that bolts in front of the motor and uses quick change gears [i believe]that we looked into but we did'nt have enough room for it and it cost 3000$. Procharger has the phone#. Like bvillercr says they run cogs on their race blowers for a reason. Doug only runs about 15lbs boost, put in 25 or 30 and make it come alive. After messing with mechanical fuel injection i suggest blowing into a big 4 barrel carb. Their's an engine builder making over 1700 hp with a big chev an F2 -4 Barrel -pump gas and cog belt. Steve Morrison i believe.

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing." Helen Keller